1. Field of the Invention
The present invention relates to an image forming apparatus that thermally transfers an image that has been formed by exposing a photosensitive material, from the photosensitive material to an image-receiving material.
2. Description of the Related Art
A thermal transfer-type image forming apparatus transfers an image on a photosensitive material, which image was formed through imagewise exposure, to an image-receiving material. This type of image forming apparatus is ordinarily structured such that the photosensitive material is pulled out a predetermined length from a magazine, cut into the form of a sheet, and then sent to an exposure section.
After applying water to the photosensitive material that has been exposed at the exposure section, the photosensitive material is laminated with the image-receiving material and wound at a heating drum to be pressed against the heating drum for a predetermined period of time with an endless belt, thereby thermally transferring an image from the photosensitive material to the image-receiving material.
However, with such a structure, there is the necessity of making the diameter of the heating drum large in accordance with the size of the image to be transferred, and in conjunction, the length of the endless belt must be long. Therefore, the apparatus cannot be made compact.
Further, with such a structure, after the image has been transferred, disposing of the sheet-form photosensitive material in a bundled state is difficult.
The present invention was achieved in light of the above-described circumstances, and an object thereof is to make processing of used photosensitive material easy and to allow the size of an image forming apparatus to be reduced.
In the present invention, a photosensitive material supplying device pulls out a photosensitive material, which is in the form of a roll, and feeds it to an exposure section. The photosensitive material is exposed at the exposure section. Thereafter, a solvent is applied to the photosensitive material by an application device, and the photosensitive material is conveyed to a heating drum.
An image-receiving material supplying device pulls out an image-receiving material, which is in the form of a roll, cuts it to a desired size, and winds it at a heating drum. Simultaneously, at the heating drum, a laminating device laminates the image-receiving material and the photosensitive material, to which a solvent has been applied.
The heating drum, at which the photosensitive material and the image-receiving material have been wound, is rotated without being stopped, and while the photosensitive material and the image-receiving material are conveyed, an image on the photosensitive material is thermally transferred to the image-receiving material. Accordingly, the time taken for the image-receiving material, which has had the image thermally transferred thereto, to be discharged from the image forming apparatus is reduced.
Increasing the radius of the heating drum in accordance with the size of the image to be thermally transferred is not necessary as it is in conventional image forming apparatuses. An endless belt is also not necessary. Accordingly, the apparatus can be made compact.
Further, since the photosensitive material is conveyed from the photosensitive material-supplying device to a take-up device without being cut, the photosensitive material itself functions as an endless belt that applies a fixed pressure.
Since the photosensitive material that has been laminated with the image-receiving material is taken up by the take-up device without being cut into sheet-forms, processing of the used photosensitive material is made easy.
In the present invention, the laminating device preferably comprises: laminating rollers that rotate around the heating drum in a state where the photosensitive material and the image-receiving material are interposed between the laminating rollers and the heating drum; and a stripping device that strips a trailing-end side of the photosensitive material off from the heating drum, in conjunction with rotation of the laminating roller.
Taking as an example a case where image processing is carried out for a single sheet, the image-receiving material is conveyed to the heating drum after being cut into a sheet-form, which does not cause problems. The photosensitive material, however, continuously extends until the photosensitive material supplying device, since it is taken up by the take-up device.
When the photosensitive material is conveyed without being cut, after the image is transferred to the image-receiving material, regions of the photosensitive material that have not been exposed imagewise may contact the heating drum as the heating drum rotates. These regions of the photosensitive material can not be used for the subsequent image processing.
Accordingly, in a preferred embodiment of the present invention a structure has been adopted wherein the laminating rollers rotate about the heating drum with the photosensitive material and the image-receiving material interposed between the heating drum and the laminating rollers. The stripping device strips the trailing-end side of the photosensitive material off from the heating drum, in conjunction with movement of the laminating roller.
Namely, while maintaining a state in which the trailing end portion of the sheet-form image-receiving material and the photosensitive material are laminated together with the laminating rollers, the stripping device strips away from the heating drum the side of the photosensitive material towards the photosensitive material supplying device. Accordingly, the photosensitive material that has not yet been exposed does not contact the heating drum, and can be used in the next image formation processing.
In the present invention, a swinging device preferably supports an application unit provided with an application portion for applying a solvent, such that the application unit can be swung. A driving device rotates the application unit while causing the application portion to contact the photosensitive material at an angle such that the entire surface of the application portion is gradually brought into contact with the photosensitive material. Air is removed from between the surface of the photosensitive material and the application portion, thereby preventing uneven application.
According to another aspect of the present invention, the take-up device comprises: a core; a holding member swingably attached to the core, for holding an end portion of the photosensitive material against the core; an engaging pawl protruding from the core for penetrating the photosensitive material and passing therethrough; a flange provided at two ends of the core, at least one of the flanges being detachable; and a releasing device for collapsing the engaging pawl when the photosensitive material has been wound around the core, and is to be pulled therefrom in an axial direction of the core.
According to this structure, the holding member is collapsed toward the core, and an end portion of the photosensitive material is thereby held down by the holding member. The engaging pawl that is provided at the core so as to protrude therefrom is made to pass through the photosensitive material. Accordingly, the photosensitive material does not become removed from between the core and the holding member.
The flange that is provided at each of the two ends of the core prevents the photosensitive material from shifting sideways when the photosensitive material that has been used is taken up. At least one of the flanges is attached such that detachment is possible. After all of the used photosensitive material is taken up, the flange can be removed, and the photosensitive material, which is in the form of a roll, can be pulled out in the shaft direction of the core.
At this time, the releasing device functions to collapse the engaging pawl, which has been passed through the photosensitive material. Accordingly, the photosensitive material, which is in the form of a roll, can be removed without using much force.